// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_
#define CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_

#include <map>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/optional.h"
#include "base/strings/nullable_string16.h"
#include "base/strings/string16.h"
#include "content/browser/bad_message.h"
#include "content/common/content_export.h"
#include "content/common/dom_storage/dom_storage_types.h"

class GURL;

namespace content {

class DOMStorageContextImpl;
class DOMStorageHost;
class DOMStorageNamespace;
class DOMStorageArea;

// One instance is allocated in the main process for each client process.
// Used by DOMStorageMessageFilter in Chrome.
// This class is single threaded, and performs blocking file reads/writes,
// so it shouldn't be used on chrome's IO thread.
// See class comments for DOMStorageContextImpl for a larger overview.
class CONTENT_EXPORT DOMStorageHost {
public:
    explicit DOMStorageHost(DOMStorageContextImpl* context);
    ~DOMStorageHost();

    base::Optional<bad_message::BadMessageReason>
    OpenStorageArea(int connection_id,
        int namespace_id,
        const GURL& origin);
    void CloseStorageArea(int connection_id);
    bool ExtractAreaValues(int connection_id, DOMStorageValuesMap* map);
    unsigned GetAreaLength(int connection_id);
    base::NullableString16 GetAreaKey(int connection_id, unsigned index);
    base::NullableString16 GetAreaItem(int connection_id,
        const base::string16& key);
    bool SetAreaItem(int connection_id, const base::string16& key,
        const base::string16& value, const GURL& page_url,
        base::NullableString16* old_value);
    bool RemoveAreaItem(int connection_id,
        const base::string16& key,
        const GURL& page_url,
        base::string16* old_value);
    bool ClearArea(int connection_id, const GURL& page_url);
    bool HasAreaOpen(int namespace_id, const GURL& origin) const;
    bool HasConnection(int connection_id) const
    {
        return !!GetOpenArea(connection_id);
    }

private:
    // Struct to hold references needed for areas that are open
    // within our associated client process.
    struct NamespaceAndArea {
        scoped_refptr<DOMStorageNamespace> namespace_;
        scoped_refptr<DOMStorageArea> area_;
        NamespaceAndArea();
        NamespaceAndArea(const NamespaceAndArea& other);
        ~NamespaceAndArea();
    };
    typedef std::map<int, NamespaceAndArea> AreaMap;

    DOMStorageArea* GetOpenArea(int connection_id) const;
    DOMStorageNamespace* GetNamespace(int connection_id) const;

    scoped_refptr<DOMStorageContextImpl> context_;
    AreaMap connections_;

    DISALLOW_COPY_AND_ASSIGN(DOMStorageHost);
};

} // namespace content

#endif // CONTENT_BROWSER_DOM_STORAGE_DOM_STORAGE_HOST_H_
